<template>
	<view class="content">
		<scroll-view scroll-y class="left-aside">
			<view v-for="item in flist" :key="item.id" class="f-item b-b" :class="{active: item.id === currentId}" @click="tabtap(item)">
				{{item.name}}
			</view>
		</scroll-view>
		<scroll-view scroll-with-animation scroll-y class="right-aside" @scroll="asideScroll" :scroll-top="tabScrollTop">
			<template v-if="slist.length > 0">
				<view v-for="item in slist" :key="item.id" class="s-list" :id="'main-'+item.id">
					<text class="s-item">{{item.name}}</text>
					<view class="t-list">
						<view @click="navToList(item.id, titem.id)" v-if="titem.pid === item.id" class="t-item text-cut" v-for="titem in tlist" :key="titem.id">
							<image :src="titem.resources.img  | smallImage(80)" lazy-load></image>
							<text class="text-cut text-center">{{titem.name}}</text>
						</view>
					</view>
				</view>
			</template>
			<template v-else>
				<view v-for="item in flist" :key="item.id" class="s-list" :id="'main-'+item.id">
					<text class="s-item"></text>
					<view class="t-list">
						<view @click="navToList(0, titem.id)" v-if="titem.pid === item.id" class="t-item text-cut" v-for="titem in tlist" :key="titem.id">
							<image mode="aspectFit" :src="titem.resources.img  | smallImage(80)" lazy-load></image>
							<text class="text-cut text-center">{{titem.name}}</text>
						</view>
					</view>
				</view>
			</template>
		</scroll-view>
	</view>
</template>

<script>
	import Good from '../../api/good'
	export default {
		data() {
			return {
				sizeCalcState: false,
				tabScrollTop: 0,
				currentId: 49,	//一级类目默认选中的ID
				flist: [],
				slist: [],
				tlist: [],
				tap: 0,
			}
		},
		onLoad(){
			this.loadData();
		},
		methods: {
			async loadData(){
				const that = this
				// 分类
				await Good.goodCategory({},function(res){
					res.forEach(item=>{
						if(!item.pid){
							that.flist.push(item);  //pid为父级id, 没有pid或者pid=0是一级分类
						}else if(!item.resources){
							that.slist.push(item); //没有图的是2级分类
						}else{
							that.tlist.push(item); //3级分类
						}
					})
					setTimeout(() => {
					  if(!that.sizeCalcState){
					  	that.calcSize();
					  }
					}, 1)
				})
			},
			//一级分类点击
			tabtap(item){
				if(!this.sizeCalcState){
					this.calcSize();
				}
				this.tap = 1
				this.currentId = item.id;
				if (this.slist.length>0) {
					let index = this.slist.findIndex(sitem=>sitem.pid === item.id);
					if(this.tabScrollTop === this.slist[index].top){
						this.tabScrollTop = this.slist[index].top+1
					}else{
						this.tabScrollTop = this.slist[index].top
					}
				} else {
					let index = this.flist.findIndex(sitem=>sitem.id === item.id);
					if(this.tabScrollTop === this.flist[index].top){
						this.tabScrollTop = this.flist[index].top+1
					}else{
						this.tabScrollTop = this.flist[index].top
					}
				}

			},
			//右侧栏滚动
			asideScroll(e){
				if(!this.sizeCalcState){
					this.calcSize();
				}
				let scrollTop = e.detail.scrollTop;
				let tabs = null
				if (this.slist.length>0) {
					tabs = this.slist.filter(item=>item.top <= scrollTop).reverse();
					if(tabs.length > 0 && !this.tap){
						this.currentId = tabs[0].pid;
					}
				} else {
					tabs = this.flist.filter(item=>item.top <= scrollTop).reverse();
					if(tabs.length > 0 && !this.tap){
						this.currentId = tabs[0].id;
					}
				}

				this.tap = 0
			},
			//计算右侧栏每个tab的高度等信息
			calcSize(){
				let h = 0;
				if (this.slist.length>0) {
					this.slist.forEach(item=>{
						let view = uni.createSelectorQuery().select("#main-" + item.id);
						view.fields({
							size: true
						}, data => {
							item.top = h;
							h += data.height;
							item.bottom = h;
						}).exec();
					})
				} else {
					this.flist.forEach(item=>{
						let view = uni.createSelectorQuery().select("#main-" + item.id);
						view.fields({
							size: true
						}, data => {
							if(h === 0){
								this.currentId = item.id
							}
							item.top = h;
							h += data.height;
							item.bottom = h;
						}).exec();
					})
				}
				this.sizeCalcState = true;
			},
			navToList(sid, tid){
				uni.navigateTo({
					url: `/pages/product/list?fid=${this.currentId}&sid=${sid}&tid=${tid}`
				})
			}
		}
	}
</script>

<style lang='scss'>
	page,
	.content {
		height: 100%;
		background-color: #f8f8f8;
	}

	.content {
		display: flex;
	}
	.left-aside {
		flex-shrink: 0;
		width: 200upx;
		height: 100%;
		background-color: #fff;
	}
	.f-item {
		display: flex;
		align-items: center;
		justify-content: center;
		width: 100%;
		height: 100upx;
		font-size: 28upx;
		color: $font-color-base;
		position: relative;
		&.active{
			color: $base-color;
			background: #f8f8f8;
			&:before{
				content: '';
				position: absolute;
				left: 0;
				top: 50%;
				transform: translateY(-50%);
				height: 36upx;
				width: 8upx;
				background-color: $base-color;
				border-radius: 0 4px 4px 0;
				opacity: .8;
			}
		}
	}

	.right-aside{
		flex: 1;
		overflow: hidden;
		padding-left: 20upx;
	}
	.s-item{
		display: flex;
		align-items: center;
		height: 70upx;
		padding-top: 8upx;
		font-size: 28upx;
		color: $font-color-dark;
	}
	.t-list{
		display: flex;
		flex-wrap: wrap;
		width: 100%;
		background: #fff;
		padding-top: 12upx;
		&:after{
			content: '';
			flex: 99;
			height: 0;
		}
	}
	.t-item{
		flex-shrink: 0;
		display: flex;
		justify-content: center;
		align-items: center;
		flex-direction: column;
		width: 176upx;
		font-size: 26upx;
		color: #666;
		padding-bottom: 20upx;

		image{
			width: 140upx;
			height: 140upx;
		}
		.text-cut{
			width: 176upx;
		}
	}
</style>
